$ { \left[\begin{array}{r}{-1} \\ {3} \\ {-1}\end{array}\right]-\left[\begin{array}{r}{1} \\ {1} \\ {4}\end{array}\right] = {?} } $
Solution: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{r}{-1}-{1} \\ {3}-{1} \\ {-1}-{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{-2} \\ {2} \\ {-5}\end{array}\right]}$